Fairlady Z top speed problem....

[Muzaffar]

Sorry if this has been already posted

Well after watching Wangan Midnight yesterday i thought i would try out to see how fast the Fairlady Z was going. (it was the Fairlady Z 300ZX (Z31) '83 model for your information) I did tune the car to its maximum buying all the parts and putting S3 tires. I tried to have a practice on the Test Course and race with the A.I.'s. Well the car produced around 580hp with Nos. The car could hit 400 km/h on the straights!

But there's one problem, i tried to slipstream the AI to get some extra speed but when i tried to overtake, the rear lose grip and spun off! I tried both with and without TSC and ASM but it still have a problem. I didn't have a rear spoiler or used racing tires just yet. But is there any way i can tune the suspension to make the car grip better at the rear without using a wing and racing tires? I'll try to post the settings i used for the car tomorrow.

 

[Parnelli Bone]

Sorry if this has been already posted

Well after watching Wangan Midnight yesterday i thought i would try out to see how fast the Fairlady Z was going. (it was the Fairlady Z 300ZX (Z31) '83 model for your information) I did tune the car to its maximum buying all the parts and putting S3 tires. I tried to have a practice on the Test Course and race with the A.I.'s. Well the car produced around 580hp with Nos. The car could hit 400 km/h on the straights!

But there's one problem, i tried to slipstream the AI to get some extra speed but when i tried to overtake, the rear lose grip and spun off! I tried both with and without TSC and ASM but it still have a problem. I didn't have a rear spoiler or used racing tires just yet. But is there any way i can tune the suspension to make the car grip better at the rear without using a wing and racing tires? I'll try to post the settings i used for the car tomorrow.

...yeah i was gonna say, try posting your settings. Let's start there.

 

[Leonidae]

I'm willing to guess that moving out of the slipstream caused downforce to the front of the Z31 and lifting force to the rear due the shape of the car, which is just realistic.

 

[Muzaffar]

Well here are my settings:

Parts:
Racing Exhaust
Racing Brakes
Brake Balance Controller
Original Turbine Kit
Port Polishing
Engine Balancing
Racing Chip
Nitrous
FC Transmission
Triple-plate Clutch
Racing Flywheel
FC LSD
Original Suspension
S3 Tyres
Weight Reduction Stage 3
Oil Change

Nitrous: 70

Suspension
Spring Rate: 14.8 / 14.2
Ride Height: 83 / 83
Shock Absorbers: 7 / 7
Camber: 2.0 / 1.0
Toe: 0 / 0
Stabilizers: 4 / 4

Brake Controller
Brakes: 10 / 10

Gear Ratios
1st: 2.505
2nd: 1.580
3rd: 1.110
4th: 0.821
5th: 0.640
6th: 0.525
Final Gear: 3.545

Autoset 25

LSD
Initial: 10
Acceleration: 40
Deceleration: 20

Driving Aids
ASM Oversteer: 0 / 10
ASM Understeer: 0 / 10
TCS: 0 /5

I'm willing to guess that moving out of the slipstream caused downforce to the front of the Z31 and lifting force to the rear due the shape of the car, which is just realistic.

Yeah, i think what your saying is right. Can't blame the car for that But it also happens when i'm turning at the banking. If i turn slightly too much the rear feels very loose and almost started to slide. But is there any way to counter that?

 

[Leonidae]

Suspension
Spring Rate: 14.8 / 14.2 <- This is a very light car, thus high spring ratios aren't needed. drop the front end around half of that value and rear end to around 5.0-7.0
Ride Height: 83 / 83 <- lowered all the way? not good. you need suspension travel, otherwise suspension won't work as it should. set the values atleast 20mm above minimum
Shock Absorbers: 7 / 7 <- Softer front dampers will allow the car react faster to the weight shifting techniques.
Camber: 2.0 / 1.0
Toe: 0 / 0 < try different toe values, like 1/-2 for improved turning ability.
Stabilizers: 4 / 4 < these will affect to cars handling greatly. greater value in front makes car understeer, smaller oversteer. in the rear end it's other way round.

Brake Controller
Brakes: 10 / 10 < drop the rear brake value until you can't hear tyres squealing under braking. and if the car understeers during braking, decrease the front value as well.

Gear Ratios
1st: 2.505
2nd: 1.580
3rd: 1.110
4th: 0.821
5th: 0.640
6th: 0.525
Final Gear: 3.545

Autoset 25

LSD
Initial: 10
Acceleration: 40
Deceleration: 20

You haven't done much to the differential. let me explain how it works..

Initial increasing the number will quicken LSD's reaction to acceleration to deceleration. i usually use value 30 for RWD's, depending of power.

Acceleration: this determines how stiff the lock will be under acceleration. it stabilizes the car under acceleration, decreasing the slip of the inner tyre in the corners for example.

Deceleration: same thing, but happens during deceleration.

Adjusting the LSD too stiff causes understeer, and too open diff will cost you in form of tyre life and grip.



Driving Aids
ASM Oversteer: 0 / 10
ASM Understeer: 0 / 10
TCS: 0 /5

For pete's sake, turn these off. Devil Z has no such luxuries!

I hope this helps.

 

[Muzaffar]

Well thanks for the setups! Tried the setups already, the car seems fine now. Doesn't twitch as much during slipstreaming nor during cornering. But the car still snap oversteer when i hit the guardrail or the A.I.'s and there is little chance of me catching it! No wonder they called it "The Devil Z" Maybe only the pros could handle this beast. This could make an interesting race report if i could pull it off......

 

[Leonidae]

just keep practising hard, just like Akio did.

 

[Rockit]

i have an issue with Madfinns style of lsd tuning, it's one of the first things i noticed in your tunes that was hugely different then my own settings.

now i tried it on the black bird, and it worked, the lsd settings i mean. However i disagree with your logic on them and i feel that your high initial torque settings will limit turn in. for a novice this may be good, as i also see you guys often have high rear spring bias, increasing oversteer in general, but with a more limited ability to turn in, it ought to stabalize the car a bit.

however, does this not increase rear tire wear(in a fr), decrease response, and wax the cars power steer ability? After a good long while of going different ways with my tunes i ahve found that most of the time, the basic setup of things is the direction that most cars need to go.

In short your lsd settings work for your suspensions, but probably not for the more conventional setups nor for the guys like me that build "options" into a car, i.e. if i come in too hot to a turn i usually have an exit strategy that the car is built to use, be it trail braking or braking drift, or power over steer or brake whip. i always have these tricks built into my cars.

I'm not saying you're wrong, and your lsd is tuned to complement the suspension, but is it the fastest method(lowest lap times) in your opinion?

 

[Rotary Junkie]

And yet I have no problem with their tuning style. Hmm.

I'd say that MFT doesn't use high initial torque settings except on basketcase oversteer.

 

[Leonidae]

out of two of us, I'm the one who uses "out of the box" settings in LSD, and Greycap is the conservative one.. but I'll let him tell his opinions before I say anything else.

 

[Greycap]

i have an issue with Madfinns style of lsd tuning, it's one of the first things i noticed in your tunes that was hugely different then my own settings.

now i tried it on the black bird, and it worked, the lsd settings i mean. However i disagree with your logic on them and i feel that your high initial torque settings will limit turn in. for a novice this may be good, as i also see you guys often have high rear spring bias, increasing oversteer in general, but with a more limited ability to turn in, it ought to stabalize the car a bit.

"Having an issue" is a bit strong word here, disagreeing might sound a bit better unless you want to begin flaming again.

High initial doesn't matter a bit as the deceleration value is set to be very low. Remember, the initial only affects the LSD if there is some locking action in the diff but as you can see it's often set to 5 which means an open diff.

however, does this not increase rear tire wear(in a fr), decrease response, and wax the cars power steer ability? After a good long while of going different ways with my tunes i ahve found that most of the time, the basic setup of things is the direction that most cars need to go.

It may increase rear tyre wear, but usually it isn't a problem of any kind as the fronts are going out long before the rears (unless the car is ridiculously overpowered for the tyres it's running) so actually we're balancing the tyre wear. It definitely doesn't decrease response, the stiff rear is more eager to respond to the movements of the front than a squashy soft setup. And I have no idea what you mean by power steer ability, but if it's power oversteer it can effectively increase it in underpowered cars by enabling the rear tyres to be overloaded in hard acceleration.

The base setups are always the "safe settings" and while they may produce cars that are easy to drive - and ones that frustrate an experienced driver as they can't be driven as hard as one wants - they are very seldom the fastest way to go.

In short your lsd settings work for your suspensions, but probably not for the more conventional setups nor for the guys like me that build "options" into a car, i.e. if i come in too hot to a turn i usually have an exit strategy that the car is built to use, be it trail braking or braking drift, or power over steer or brake whip. i always have these tricks built into my cars.

If our settings work for our suspensions, what are you complaining about? I don't think we're forcing you to use them on your cars. And believe me, our cars have tricks too - ones that need to be mastered or the car is more than a handful.

I'm not saying you're wrong, and your lsd is tuned to complement the suspension, but is it the fastest method(lowest lap times) in your opinion?

Oh yes. We wouldn't be using it if it wasn't just that. And if you take a closer look at the setups, Leonidae's settings can be dramatically different from mine. What works for him, may not work for me. Every car is different because every driver is different and the car must reflect the style of the driver.

 

[sucahyo]

But the car still snap oversteer when i hit the guardrail or the A.I.'s and there is little chance of me catching it! No wonder they called it "The Devil Z"

try high front damper, low rear damper. high front - low rear stabilizer if possible.

 

[Parnelli Bone]

Oh yes. We wouldn't be using it if it wasn't just that. And if you take a closer look at the setups, Leonidae's settings can be dramatically different from mine. What works for him, may not work for me. Every car is different because every driver is different and the car must reflect the style of the driver.

This is what i've been saying for years online. There's no single "magic" setup. It varies from car to car and even driver to driver according to our specific styles of driving/racing.

But the car still snap oversteer when i hit the guardrail or the A.I.'s and there is little chance of me catching it! D

Don't hit the Ai and guardrails, then! Why would you want to in the first place?